Problems resulting from alcohol consumption by drivers have been studied worldwide, and epidemiological research points to high injury and death rates related to drinking-and-driving. However, equivalent data are limited in Brazil. In this study, 913 drivers were stopped on public roads with heavy traffic and high concentrations of bars, restaurants, and nightclubs in Belo Horizonte, Minas Gerais State, and asked to answer a questionnaire and submit to an active breathalyzer test. The study was done in December 2005 and December 2006. The study adopted the internationally accepted sobriety checkpoint method. In the sample, 38.0% of drivers showed some trace of alcohol in their exhaled air, and 19.6% were at or above the legal limit (0.6g/l). These figures were five times those found in similar surveys in other countries. The findings suggest a critical drinking-and-driving problem in Belo Horizonte (and probably elsewhere in Brazil) and the need for on-going research, the development of specific public policies to deal with the problem, and effective enforcement of the existing law.